Radial saw blade and hub for osteotomy

ABSTRACT

A saw blade includes a main body having a first surface, a second surface on an opposite side of the main body from the first surface, a proximal edge portion, a distal edge portion, and first and second side portions extending between the proximal and distal edge portions. The proximal edge portion is configured to be coupled to a rotatable hub such that the saw blade is held in a curved shape with the first surface defining an outer radius when the saw blade is coupled to the rotatable hub. The distal edge portion includes a plurality of cutting teeth, and the second surface includes a cutting structure configured such that a radius of an arc swept by the cutting structure when the saw blade is rotated is substantially equal to the outer radius of the first surface.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/420,437, filed Nov. 10, 2016, which is incorporated by referenceherein in its entirety.

FIELD

This application pertains to saw blades and hub assemblies for osteotomyprocedures.

BACKGROUND

Radial saw blades used to create osteotomies during orthopedicprocedures remove bone material as the cut is made. Depending upon theprocedure, the resultant cut surfaces may be repositioned against eachother and stabilized with bone plates, screws, or other devices. Largegaps between the two osteotomy surfaces created by the geometry of thesaw blade can result in instability when the surfaces are mated. Thiscan lengthen recovery time, and increase the potential forpost-operative complications. Additionally, many existing blade and hubdesigns are complex and costly to manufacture, making frequentreplacement cost-prohibitive. Accordingly, a need exists for improvedsaw blades for osteotomy procedures.

SUMMARY

Certain embodiments of the disclosure concern radial saw blades and hubmembers that can be used to create osteotomies during orthopedicprocedures remove bone material as the cut is made. In a representativeembodiment, a saw blade comprises a main body including a first surface,a second surface on an opposite side of the main body from the firstsurface, a proximal edge portion, a distal edge portion, and first andsecond side portions extending between the proximal and distal edgeportions. The proximal edge portion comprises a U-shaped recessextending distally from the proximal edge portion. The proximal edgeportion is configured to be coupled to a rotatable hub such that the sawblade is held in a curved shape with the first surface defining an outerradius when the saw blade is coupled to the rotatable hub. The distaledge portion comprises a plurality of cutting teeth, and the saw bladehas a thickness of from 0.005 inch to 0.018 inch.

In another representative embodiment, an assembly comprises a hub memberincluding a hub portion and a curved coupling portion. The couplingportion is radially offset from the hub portion with respect to alongitudinal axis of the hub portion about which the hub member isconfigured to rotate. The coupling portion includes a slot defined in adistal surface of the coupling portion. The hub member further includesat least one opening defined in a proximal surface of the hub member,and the at least one opening is in fluid communication with the slot ofthe coupling portion. The assembly further comprises a blade received inthe slot of the coupling portion. The blade includes at least one tabportion extending through the opening in the proximal surface of the hubmember and folded over to engage the hub member.

In another representative embodiment, an assembly comprises a hub memberincluding a hub portion and a curved coupling portion. The couplingportion is radially offset from the hub portion with respect to alongitudinal axis of the hub portion about which the hub member isconfigured to rotate. The coupling portion includes a first extensionportion extending from a first side portion of the coupling portion, anda second extension portion extending from a second side portion of thecoupling portion opposite the first side portion. The hub member furthercomprises a third extension portion extending from a central portion ofthe coupling portion, and a fourth extension portion extending from thecentral portion and radially offset from the third coupling portion suchthat the third and fourth extension portions are spaced apart from eachother relative to the longitudinal axis of the hub portion. The assemblyfurther comprises a blade coupled to the hub member such that the bladeis situated on the first and second extension portions, and receivedbetween the third and fourth extension portions of the coupling portion.The blade includes a U-shaped recess. The assembly further includes afastener extending through the third extension portion, the U-shapedrecess of the blade, and the fourth extension portion to secure theblade to the hub member.

In another representative embodiment, an assembly comprises a hub memberincluding a hub portion and a curved coupling portion, the couplingportion being radially offset from the hub portion with respect to alongitudinal axis of the hub portion about which the hub member isconfigured to rotate. The coupling portion comprises at least oneextension portion configured to receive a blade. The assembly furthercomprises an elongated guide member couplable to the hub portion of thehub member and configured to extend along the longitudinal axis of themounting portion.

In another aspect, the assembly further comprises a clamping memberconfigured to clamp a blade between the clamping member and the at leastone extension portion.

In another aspect, the coupling portion includes an upper extensionportion and three lower extension portions radially offset from theupper extension portion with respect to the longitudinal axis of the hubmember such that a blade can be received between the upper extensionportion and the lower extension portions.

In another aspect, at least one of the lower extension portions includesa post configured to be received in a corresponding opening defined in ablade when a blade is coupled to the coupling portion.

In another aspect, the hub portion of the hub member defines an opening,and the assembly further comprises a magnet disposed in the opening tomagnetically engage the guide member.

In another aspect, the hub member includes a pair of arms extendingbetween the hub portion of the hub member and the coupling portion ofthe hub member.

In another representative embodiment, a method comprises drilling aguide hole in a bone, and inserting a guide member of a hub assemblyinto the guide hole. The hub assembly comprises a hub member including ahub portion and a curved coupling portion. The coupling portion isradially offset from the hub portion with respect to a longitudinal axisof the hub portion about which the hub member is configured to rotate.The coupling portion comprises at least one extension portion on which ablade is received, and the guide member is coupled to the hub portion ofthe hub member such that the guide member extends along the longitudinalaxis of the hub portion. The method further comprises cutting the bonewith the blade.

In another aspect, the blade comprises a main body including a firstsurface and a second surface. The second surface is on an opposite sideof the main body from the first surface, and the first surface definesan outer radius. The second surface comprises a cutting structureconfigured such that a radius of an arc swept by the cutting structurewhen the blade is rotated is substantially equal to the outer radius ofthe first surface.

In another representative embodiment, a saw blade comprises a main bodyincluding a first surface, a second surface on an opposite side of themain body from the first surface, a proximal edge portion, a distal edgeportion, and first and second side portions extending between theproximal and distal edge portions. The proximal edge portion isconfigured to be coupled to a rotatable hub such that the saw blade isheld in a curved shape with the first surface defining an outer radiuswhen the saw blade is coupled to the rotatable hub. The distal edgeportion comprises a plurality of cutting teeth, and the second surfacecomprises a cutting structure configured such that a radius of an arcswept by the cutting structure when the saw blade is rotated issubstantially equal to the outer radius of the first surface.

In another aspect, the cutting structure comprises a plurality ofprojections.

In another aspect, the projections are rounded lobes.

In another aspect, the projections comprise cutting surfaces oriented inthe direction of at least one of the side portions of the main body.

In another aspect, a distal edge of the cutting structure is proximallyoffset from the distal edge portion of the main body.

In another aspect, first and second side portions of the cuttingstructure are offset from the first and second side portions of the mainbody toward a longitudinal axis of the main body.

In another aspect, a thickness of the main body increases along at leasta portion of a width dimension of the main body from the first sideportion in a direction toward a longitudinal axis of the main body, andin a direction from the second side portion toward the longitudinal axisof the main body.

In another aspect, the cutting structure comprises a plurality of ridgesextending along the second surface.

In another aspect, the heights of the apices of the ridges vary alongthe main body.

In another aspect, the cutting teeth extend from respective ridges ofthe cutting structure.

In another aspect, width dimensions of respective base portions of thecutting teeth vary along a width dimension of the saw blade.

In another aspect, the width dimensions of base portions of cuttingteeth adjacent the first and second side portions are greater than thewidth dimensions of cutting teeth adjacent a longitudinal axis of thesaw blade.

The foregoing and other objects, features, and advantages of thedisclosed technology will become more apparent from the followingdetailed description, which proceeds with reference to the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are representative examples of saw blades that can be used inthe osteotomy procedures described herein.

FIGS. 4A-4C illustrate a representative tibial plateau levelingosteotomy (TPLO) procedure.

FIGS. 5A-5C illustrate a representative repair of a ruptured cranialcruciate ligament by performing a TPLO.

FIGS. 6A and 6B illustrate the effects of saw blade thickness on anosteotomy site.

FIGS. 7A-7C illustrate the effects of saw blade thickness on therespective radii of the cut bone surface and the surface of the bonesegment.

FIGS. 8-10 illustrate a representative embodiment of a radial saw bladewith a thickness that varies along the cross-section of the blade.

FIGS. 11-13 illustrate another embodiment of a radial saw blade with avarying thickness and a cutting structure on the radially inward surfaceof the blade.

FIGS. 14A and 14B illustrate an embodiment of the cutting structure ofthe blade of FIGS. 11-13 in greater detail.

FIG. 15 illustrates another embodiment of the blade of FIGS. 11-13.

FIGS. 16 and 17 illustrate another embodiment of a radial saw bladewhere the radially inward surface of the blade has a cutting structurecomprising a plurality of longitudinally extending ridges.

FIG. 18 illustrates another embodiment of a radial saw blade whereinangles formed by the sides of the cutting teeth vary along the width ofthe blade.

FIG. 19 is a side elevation view of a tibia illustrating the contours ofan osteotomy performed with a conventional radial saw blade.

FIG. 20 is a side elevation view of a tibia illustrating the contours ofan osteotomy performed with the saw blade of FIGS. 11-13.

FIG. 21 is a perspective view of a representative embodiment of a hubassembly.

FIG. 22 is a side elevation view of the hub assembly of FIG. 21

FIG. 23 is a bottom plan view of the hub assembly of FIG. 21.

FIG. 24 is an exploded view of the hub assembly of FIG. 21.

FIGS. 25A and 25B are perspective views of another embodiment of a hubassembly.

FIG. 26 is a top plan view of the hub assembly of FIGS. 25A and 25B.

FIG. 27 is a bottom plan view of the hub assembly of FIGS. 25A and 25B.

FIGS. 28 and 29 illustrate the process of securing a radial saw blade tothe hub assembly of FIGS. 25A and 25B.

FIG. 30 is a perspective view illustrating a test of the radial sawblade of FIGS. 11-13.

FIG. 31 is a perspective view of a hub assembly, according to anotherembodiment.

FIG. 32 is a perspective view of the hub assembly of FIG. 31illustrating lower surfaces of the hub member and the blade.

FIG. 33 is a perspective view of the hub assembly of FIG. 31illustrating the blade separated from the hub member.

FIGS. 34 and 35 are perspective views of another embodiment of a hubassembly including a molded or additively manufactured hub member.

FIG. 36 is a perspective view illustrating attachment of the blade tothe hub member of the hub assembly of FIG. 34.

FIG. 37 is a perspective view illustrating the hub assembly of FIG. 34prior to attachment of the chuck member.

FIG. 38 is a rear perspective view of the hub assembly of FIG. 34illustrating a proximal surface of the hub member.

FIGS. 39 and 39A are a cross-sectional side views of the hub assembly ofFIG. 34.

FIG. 40A is a side elevation view illustrating a cut made in a foamblock using an embodiment of a radial saw blade having a thickness of0.012 inch.

FIGS. 40B and 40C are side elevation views illustrating cuts made infoam blocks using conventional saw blades.

FIG. 41 is a graph illustrating the decline in cutting efficiency of asaw blade as the number of uses increases.

DETAILED DESCRIPTION

In human and animal orthopedics, various saw blades are available tomake osteotomies in bone. Straight osteotomies, radial osteotomies, andspherical osteotomies can be created at specific locations in long bonesto achieve realignment of a bone segment to the overall limb axis forimproved biomechanics. Representative examples of a flat saw blade, aradial saw blade, and a spherical or dome saw blade are shown in FIGS.1-3, respectively.

There are multiple physiological problems associated with long bonesthat can affect limb biomechanics, which can occur as a result of trauma(e.g., bone fractures that heal in a misaligned position), or birthdefects. Surgical methods of re-establishing appropriate biomechanics ofa limb can include repositioning proximal and distal bone segments tocorrect alignment issues. There are clinical examples for many longbones (e.g., femur, tibia, humerus, radius, ulna, etc.), which can bemanaged through corrective osteotomies to restore improved limb functionin which a portion of the bone (referred to herein as a “bone segment”or “excised portion”) is excised from the remainder of the bone, andreattached to the bone in a specified position and/or orientation toaddress the subject pathology. With reference to the femur, there areproximal and distal corrective osteotomies that can address differentbiomechanical alignment issues.

For example, in veterinary medicine, a tibial plateau leveling osteotomy(TPLO) can be performed to re-position the tibial plateau to, forexample, function as a buttress to resist certain physiologicalmovements or address rupture of the anterior (cranial) cruciateligament. FIGS. 4A-4C illustrate a representative example of a TPLOprocedure. FIG. 4A illustrates a normal angle θ between a plane 52defined by the tibial plateau 54 and a horizontal reference plane 56. Incertain circumstances, it can be beneficial to rotate the plane 52 ofthe tibial plateau 54 to reduce the angle between the tibial plateau andthe reference plane 56. This can be accomplished by creating a radialcut in a proximal portion 58 of the tibia 60 and rotating the excisedportion 62 such that the angle between the tibial plateau 54 and thehorizontal reference plane 56 is lowered (e.g., to about 6 degrees insome embodiments), as shown in FIGS. 4B and 4C.

A TPLO procedure may be performed to compensate for ruptures of thecranial cruciate ligament (for example, in dogs). A representativeexample of a TPLO to repair a ruptured cranial cruciate ligament isillustrated in FIGS. 5A-5C. As illustrated in FIG. 5A, the cranialcruciate ligament 76 can extend between the femur 78 and the tibia 80,and can resist advancement of the tibia in the direction indicated byarrow 82 due to force applied to the tibia by the femur. FIG. 5Billustrates forward advancement of the tibia 80 in the direction ofarrow 82 due to rupture of the cranial cruciate ligament 76. In atypical example, an osteotomy using any of the saw blades disclosedherein can be made in the lateral plane on the medial side of the tibia80 to reduce the angle θ (FIG. 4A) of the tibial plateau 84 with respectto a horizontal reference plane 86, as illustrated in FIG. 5C. This cancreate a mechanical abutment in the caudal aspect of the knee, assistingthe soft tissues in preventing the femur from sliding off the back ofthe tibia, mitigating the effects of a non-functional cranial cruciateligament.

In certain configurations, radial saw blades used for TPLO procedurescan be one-piece constructs, or assemblies of two or more separatecomponents, such as a hub and detachable blade. In certain examples, theblade oscillates along an arc having a radius substantially equal to aradius of the blade. For example, the blade may move through an angle ofabout ±8 degrees with a frequency of about 500 Hz to about 1,000 Hz.Blades may be used for multiple surgical procedures, and can bediscarded or sharpened when, for example, the blade fails to performadequately intraoperatively. Some indications of blade failure includeinadequate advancement of the blade through the bone, burning of thebone, and/or breakage of the blade. In some embodiments, blades may beused about 20 times, or as many as 100 times. However, in certaincircumstances, a blade may begin to generate excessive heat after only afew uses. When temperatures of over 47° C. are generated at the boneinterface, necrosis may occur. Necrosis at the osteotomy interface candelay healing, and can increase the risk of non-union of the bone andthe excised bone segment, requiring surgical intervention. In somecases, non-union of the bone and the excised portion at the osteotomyinterface can result in undesirable motion (e.g., micromotion) of theplate-screw reconstruction of the TPLO, which may lead to fatiguefailure of the implants.

Additionally, a radial saw blade may create a mismatch between theradius of the cut surface of the bone and the radius of the excisedportion at the osteotomy interface. This concept is illustrated in FIGS.6A and 6B, wherein a thickness t (FIG. 6B) of a radial saw blade 10results in a gap 11 between a bone 12 and an excised portion or bonesegment 14 of the bone (e before complete excision of the bone segment14). The gap 11 has a width w that corresponds to the thickness t of thesaw blade, and can result from, for example, removal or ablation of bonematerial by the saw blade 10 as the blade advances through the bone.

The resulting osteotomy surface 16 on the bone 12 and the correspondingosteotomy surface 18 on the excised bone segment 14 can have differentradii. Referring to FIG. 7A, an outer surface 20 of the saw blade 10defines a circular path 22. In certain examples, the outer surface 20 ofthe saw blade creates the osteotomy surface 16 on the bone 12 (FIG. 6A)as the blade advances through the bone. The path 22 of the outer surface20 and, thereby, the osteotomy surface 18, can have a radius r₁.Meanwhile, an inner surface 24 of the blade can define a circular path26 having a radius r₂. The inner surface 24 creates the osteotomysurface 18 of the excised bone segment 14 and, thus, the osteotomysurface 18 has a radius equal to r₂. The radius r₁ can be greater thanthe radius r₂, and the difference between the radii r₁ and r₂ can be afunction of the thickness t of the saw blade 10. Thus, thicker sawblades can result in wider gaps (e.g., more bone removed), which must beclosed and/or compressed for healing. Thicker saw blades can also resultin greater mismatch between the radii of the osteotomy surfaces. This isshown in FIGS. 7A-7C, which illustrate saw blades with increasingthickness and the resulting mismatch in radii between the osteotomysurfaces of the bone 12 and the excised portion 14. FIG. 7A illustratesa relatively thin saw blade with a thickness of, for example, about 0.25mm, FIG. 7B illustrates a blade of medium thickness (e.g., 0.65 mm), andFIG. 7C illustrates a relatively thick blade (e.g., a thickness of 1mm). The mismatches created by increased saw blade thickness cancontribute to instability and undesirable motion (e.g., rocking) whenthe osteotomy surfaces are mated, which can contribute to increasedrecovery time and potential complications (e.g., non-union of theosteotomy surfaces or implant failures).

In some cases, freehand control of the saw blade and the power saw mayalso contribute to inaccuracy in the path of the osteotomy. Generally,the cut is made perpendicular to the long axis of the bone. Existingguide tools can be cumbersome, and extensive setup is often required.Therefore, cuts may be made without guiding instruments, which canresult in inaccuracies in the plane of the cut and the cut site.

FIGS. 8 and 9 illustrate a representative embodiment of a radial sawblade 100 configured such that the radius of the inner surface is equalto or substantially equal to the radius of the outer surface. The sawblade 100 can include a main body 102 having first and second surfaces104, 106 (see FIG. 9), a proximal edge portion 108, and a distal edgeportion 110. First and second side portions 112, 114 extend between theproximal and distal edge portions 108, 110. The distal edge portion 110comprises a plurality of cutting teeth 116.

FIG. 9 illustrates a cross-sectional view of the saw blade 100 takenalong line 9-9 of FIG. 8. As illustrated in FIG. 9, the main body 102 ofthe saw blade can have a curved shape (e.g., when coupled to a hubassembly, such as the hub assembly described below) such that the firstsurface 104 defines an outer radius r₁ and the second surface 106defines an inner radius r₂. A longitudinal axis 126 of the blade isshown extending along a mid-plane of the blade. FIG. 10 illustrates asaw blade “blank” before the body of the blade is bent into a curvedshape. As illustrated in FIG. 10, the thickness of the saw blade canvary along a width dimension W₁ of the blade. For example, in theillustrated embodiment, the thickness of the saw blade can increase froma first thickness t₁ at the side portions 112, 114 to a second thicknesst₂ at or near the midpoint of the width dimension W₁ to form an apex. Inthis manner, the saw blade has a triangular cross-sectional shape. Thisvariation in thickness from the outer edges to the center of the sawblade causes the center 118 (FIG. 9) of a circle 120 defined by thesecond surface 106 to be offset from a center 122 of a circle 124defined by the first surface 104 along a longitudinal axis 126. As shownin FIG. 9, this allows the radius r₂ of the second surface 106 to beequal to or substantially equal to the radius r₁ of the first surface104. Stated differently, the radius r₂ of an arc (e.g., along circularpath 120) swept by the second surface 106 is equal to or substantiallyequal to the radius r₁ of the first surface 104. As used herein,“substantially equal” means that the radius r₂ can be 80% or more of theradius r₁, 90% or more of the radius r₁, 95% or more of the radius r₁,or 100% of the radius r₁. In this manner, the radius of a bone surfacecut by the first surface 104 will be the same or nearly the same as theradius of a corresponding surface of a bone segment cut from the bone bythe second surface 106 of the blade.

In some embodiments, the thickness t₂ can be from about 105% to about200% of the thickness t₁. In some embodiments, the thickness t₂ can be,for example, about 120% to about 150% of the thickness t₁. In someembodiments, the thickness t₂ can be about 130% of the thickness t₁. Ina representative embodiment, the thickness t₁ can be 0.012 inch and thethickness t₂ can be about 0.016 inch, such that the thickness t₂ isabout 133% of the thickness t₁.

Prior to use, the blade can be bent into a curved shape in the mannerindicated by arrows 113. The blade can be curved to achieve a variety ofradii, which can correspond to the size of the animal or the particularbone upon which an osteotomy is to be performed. Thus, in some examples,the radii r₁ and r₂ can be about 18 mm, 20 mm, 24 mm, etc. In someembodiments, the thickness of the blade can range from about 0.005 inchto about 0.020 inch. Making the blade thickness within this range can,for example, improve the speed of the cut, generate less heat, andreduce the gap at the bone interface while maintaining strength andrigidity of the blade.

FIGS. 11-13 illustrate another embodiment of the saw blade 100 whereinthe second surface 106 includes a cutting structure 128. In theillustrated embodiment, the cutting structure 128 has a length L and awidth dimension W₂, and is proximally offset from the distal edge of theblade (e.g., from the tips of the teeth 116) by a distance d. Theportion of the blade defined between the tips of the teeth 116 and thedistal edge of the cutting structure 128 is denoted portion 130. In oneexemplary embodiment, the distance d can be about 4 mm, although itshould be understood that the cutting structure 128 can be offset fromthe distal edge of the blade by any suitable distance, or can extend allthe way to the distal edge of the blade, as desired. In the illustratedembodiment, the width dimension W₂ of the cutting structure 128 issubstantially equal to the width dimension W₁ (FIG. 10) of the blade.However, in other embodiments the cutting structure need not extendacross the entire width dimension W₁ of the blade.

Referring to FIG. 12, the distal portion 130 of the blade (including theteeth 116) can have a thickness of t₁ across the full width of theblade. Referring to FIG. 13, the thickness of the portion of the bladeincluding the cutting structure 128 can vary along the width dimensionW₁ from t₁ at the side portions 112, 114 to t₂ at or near the midpointof the blade, similar to the embodiment of FIG. 8. In this manner, aradius of an arc swept by the cutting structure 28 can be equal to orsubstantially equal to the radius of the first surface 104 such thatosteotomy surfaces produced by the cutting structure 128 and the firstsurface 104 have equal or substantially equal radii. In someembodiments, the thickness of the portion of the blade including thecutting structure 128 may increase gradually with increasing distancefrom the respective side portions. In other embodiments, the thicknessmay increase over a relatively short distance, or in a step. Forexample, FIG. 15 illustrates another embodiment of the blade 100 inwhich the thickness of the main body coinciding with the cuttingstructure 128 increases in a step from t₁ to t₂ to form a raisedplatform 138 having a thickness t₂.

In certain examples, the cutting structure 128 can be a roughened ortextured portion of the second surface 106 configured to cut or abradematerial from a bone in the manner of a file. For example, withreference to FIGS. 14A and 14B, the cutting structure 128 can comprise aplurality of protrusions 132 extending from the second surface 106. Inone representative example, the protrusions can have cylindrical bases,heights of about 0.18 mm, and diameters of about 1.5 mm. In otherexamples, the protrusions can have any suitable height and any suitableshape (e.g., a triangular shape, an oval shape, pyramidal shape, etc.),or combinations of shapes. In some examples, the protrusions 132 can beformed by chemical etching of the features onto the surface of theblade.

In the illustrated configuration, the protrusions 132 can have cuttingsurfaces or faces 134. In some embodiments, the cutting surfaces 134 canbe substantially planar, and can be oriented toward either the firstside portion 112 or the second side portion 114. In this manner, thecutting surfaces 134 can be substantially perpendicular to the directionof travel of the blade when the blade is in use. For example, when usedin combination with an oscillating blade driver, the protrusions 132oriented toward the first side portion 112 can be incident upon a bonebeing cut when the blade is rotated clockwise, and the protrusions 132oriented toward the second side portion 114 can be incident upon thebone when the blade is rotated counterclockwise. This allows theprotrusions 132 of the cutting structure 128 to remove bone in bothdirections as the saw blade oscillates.

FIGS. 16 and 17 illustrate another embodiment of the blade 100 whereinthe second surface 106 includes a cutting structure comprising aplurality of ridges 140. In the illustrated embodiment, the ridges 140extend lengthwise along the second surface parallel to the longitudinalaxis 126 such that the second surface defines a plurality of peaks orapices 142 and valleys 144. The ridges 140 can be aligned with the teeth116 such that each ridge is aligned (e.g., coaxially aligned) with acorresponding tooth. Referring to FIG. 17, the height dimension H of theridges 140 can vary along the width W₁ of the blade. For example, in theillustrated embodiment, the heights H of the ridges 140 located at ornear the midpoint of the blade can be higher than the heights of theridges 140 located closer to the side portions 112, 114. In certainexamples, the teeth 116 can also extend from the apices 142 of theridges 140, through the thickness of the blade, to the first surface104. Thus, the height of the teeth 116 (e.g., at the base of the teeth)can be the same as the heights H of the corresponding ridges 140 fromwhich they extend. By varying the tooth and ridge heights along thewidth of the second surface 106, a radius r₂ of a curve 146 (e.g., acircle) defined by the apices 142 of the ridges 140 can be equal to orsubstantially equal to a radius r₁ of the first surface 104, asillustrated in FIG. 17. In this manner, the teeth 116 and/or the ridges140 can cut a bone such that the osteotomy surfaces created on bothsides of the blade have equal or substantially equal radii. The channelsdefined between the ridges 140 can also serve as conduits for irrigationfluid (e.g., saline solution), which can improve heat dissipation at thedistal end of the blade, helping to avoid overheating during anosteotomy procedure and associated tissue necrosis.

In alternative embodiments, the ridges 140 can extend at an angle to thelongitudinal axis 126 of the blade, such as perpendicular to thelongitudinal axis of the blade. In some embodiments, the angles of thesides of the teeth 116 and, hence, the width of the bases of the teeth,can be the same or different along the width of the blade, as desired.

FIG. 18 illustrates another embodiment of the blade 100 in which theangle θ formed between the sides 148 of the teeth 116 and a referenceaxis (e.g., axis 150 extending through the apex of the tooth) variesalong the width W₁ of the blade. Stated differently, the angles of thesides 148 of the teeth 116 can be varied such that a width dimension W₃of the teeth 116 varies along the width W₁ of the blade. For example, inthe illustrated embodiment, the teeth 116A, 116B nearest the edges ofthe side portions 114, 116 (e.g., at the leading and/or trailing edgesof the blade when in use) can have relatively larger angles θ than otherteeth. Thus, the widths W₃ of the bases of teeth 116A, 116B are greaterthan the widths W₃ of the bases of the teeth located at near themidpoint of the blade. This results in greater strength of the teeth116A, 116B, allowing them to withstand the higher loading attendant tobeing located at the leading edge of the blade without significantdeformation.

In the illustrated embodiment, the angle θ of the teeth 116A, 116B canbe from about 30 degrees to about 80 degrees. In an exemplaryembodiment, the angle θ of the teeth 116A, 116B can be about 45 degrees.In the illustrated configuration, the angle θ of the teeth can graduallydecrease in a direction toward the midpoint of the blade. For example,in one representative embodiment, with reference to the tooth 116A forpurposes of illustration, the angle θ of tooth 116A can be about 45degrees, and the angles of the next two teeth 116C and 116D in adirection toward the midpoint of the blade can be about 40 degrees, andabout 35 degrees, respectively. The teeth on the opposite side of theblade can have a similar configuration. Meanwhile, the teeth near themidpoint of the blade can have an angle θ of, for example, about 30degrees, although other configurations are possible. In otherembodiments, the teeth 116 at or near the midpoint of the blade can bethicker than the teeth near the side portions 112, 114, as illustratedin FIG. 17.

FIGS. 19 and 20 illustrate the fit between a bone and a bone segment cutwith the blade configurations described herein (FIG. 20) as compared toa conventional radial saw blade (FIG. 19). As shown in FIG. 19, there isa significant mismatch between the radius of a surface 204 of the bone200 and a surface 206 of the bone segment 202 cut with a conventionalradial saw blade, resulting in a relatively small contact area, andrelatively large gaps between the bone 200 and the bone segment 202 atthe ends of the radial cut. In contrast, FIG. 20 illustrates the fitbetween a bone 300 and a bone segment 302 cut from the bone 300 using aradial saw blade with the cutting structure of FIGS. 11-13. As shown inFIG. 20, the radius of the surface 304 of the bone 300 closely matchesthe radius of the surface 306 of the bone segment 302, resulting in arelatively larger area of contact between the bone and the bone segment,and relatively smaller gaps between the bone and the bone segment at theends of the radial cut.

FIGS. 21-24 illustrate a hub assembly 400 configured to receive a radialsaw blade 100, which can be configured as any of the blade embodimentsdescribed herein. The hub assembly can include a hub member 402including an upper portion configured as a hub portion 458 and a lowerportion configured as a support member 404 (also referred to as acoupling portion). The support member 404 can be coupled to the hub 402and radially offset from a longitudinal axis 454 of the hub by a pair ofarms 406, 408. In the illustrated embodiment, the longitudinal axis 454extends through the hub portion 458. The arms 406, 408 can be angledtoward one another such that the hub member 402 has a generallytriangular shape. The support member 404 can be curved, and can includea curved cradle or extension portion 456 extending from the supportmember in a direction parallel to the longitudinal axis 454. The hubportion 458 of the hub 402 can be releasably coupled to a chuck 410including a drive shaft 412, which can be received by a blade driver(e.g., a BJ2100 handpiece available from Shanghai Bojin MedicalInstrument Co., Ltd.). Rotational motion imparted to the drive shaft 412by the blade driver results in rotational motion (e.g., oscillatingrotational motion) of the hub 402 and, thus, of the blade 100, about thelongitudinal axis 454.

In the illustrated embodiment, the blade 100 can be coupled to the hubassembly by a blade coupling assembly generally indicated at 430.Referring to FIG. 24, the blade coupling assembly 430 can include aclamp member 414 and a fastener 416 configured to be inserted into anopening 420 defined in the extension portion 456. In the illustratedembodiment, the fastener 416 can have external threads on the shank, andcan also define an opening 452 extending at least partially through thelength of the fastener that can include internal threads. The blade 100can define a U-shaped recess 160 at the proximal edge portion 108 andextending distally from the proximal edge portion, and the clamp member414 can define an opening 418. When the blade 100 is positioned on theextension portion 456, the clamp member 414 can be placed over theblade, and the fastener 416 can be inserted through the opening 418 inthe clamp member, through the recess 160, and through the opening 420 inthe extension portion 456. A second fastener 422 can then be insertedinto the opening 452 in the fastener 416 such that the threads of thefastener 422 engage the internal threads of the fastener 416 to securethe blade 100 to the hub 402. The extension portion 456 (and the supportmember 404) can be curved such that the blade 100 achieves a selecteddegree of curvature when secured to the extension portion. The blade 100can be quickly and easily released from the hub by removing the fastener416.

In the illustrated embodiment, the blade coupling assembly 430 can alsoinclude a spring 432 positioned between the extension portion 456 andthe clamp member 414. The spring 432 can be configured to urge the clampmember 414 upwardly and away from the blade 100 when the fastener 416 isloosened to facilitate removal of the blade from the hub assembly.

The hub assembly 400 can also include a guide member 424. The guidemember 424 can be received in an opening 426 defined in the hub portion458 of the hub 402 such that the guide member is coaxially aligned withthe drive shaft 412. In the illustrated configuration, a magnet 428 canbe located in the opening 426 to magnetically engage a correspondingmagnet 448 on the proximal end of the guide member 424 to retain theguide member in the opening 426. This can allow the guide member 424 tobe easily attached to the hub assembly, or removed if a freehand cut isdesired. In certain examples, a guide hole can be drilled into a bone tobe cut, and the guide member 424 can be inserted into the guide holewhen the bone is cut with the blade 100 to reduce or prevent wanderingor misalignment of the blade when performing an osteotomy. In theillustrated embodiment, the guide member 424 can also include a gripportion 450 to facilitate attachment and removal of the guide memberfrom the hub assembly.

FIGS. 25A, 25B, 26, and 27 illustrate another embodiment of the hubassembly 400 in which the blade coupling assembly 430 does not requireany tools in order to secure or remove a blade from the hub. FIG. 25Ashows the hub member 402 and the chuck 410 without the blade attached.In the illustrated configuration, the support member 404 (e.g., thelower portion of the hub member 402) includes three lower extensionportions 434, 436 (see FIG. 27), and 438 spaced apart from one anotheralong the length of the support member. An upper extension portion 440extends over the lower extension portion 436. In the illustratedembodiment, the extension portions 436 and 440 extend from a centralportion of the support member 404. The extension portion 434 includes apost 442, and the extension portion 438 includes a post 444. The blade100 can define two openings 152, 154 corresponding to the posts 442,444. As shown in FIG. 25B, the blade 100 can be inserted between theextension portion 436 and the extension portion 440, and the posts 442,444 can be received in the respective openings 152, 154 of the blade tosecure the blade to the hub assembly. In some embodiments, the supportmember 404 can have a smaller radius of curvature than the blade whenthe blade is in an unconstrained state. In this manner, the blade can beurged to conform to the smaller radius of the support member 404 whencoupled to the support member, helping to keep the blade secured to thehub assembly.

FIGS. 28 and 29 illustrate a method of coupling the blade 100 to the hubassembly 400 of FIGS. 25A-27. In a representative embodiment, a user cansqueeze the blade 100 such that the blade radially deforms to a smallerradius of curvature in the manner of arrows 446. The proximal edgeportion 108 can then be inserted between the extension portions 436 and440 such that the posts 442, 444 are aligned with the openings 152, 154.The user can then release the blade such that the posts 442, 444 arereceived in the openings 152, 154 and the blade is secured to the hubassembly. This configuration allows quick coupling and removal of bladesduring operation without the use of tools if, for example, a blade needsto be replaced during an osteotomy procedure. It should also beunderstood that in alternative embodiments, the hub member 402 need notinclude arms, but can be a solid member including the support member 404offset from the hub member 402 in the manner of FIG. 6B.

FIG. 30 illustrates a test performed with a blade similar to the blade100 of FIG. 11 in a bovine femur 502. The blade was made from 440Astainless steel with a radius of 24 mm (when secured to the bladedriver) and a thickness of 0.012 inch at the edge portions. The bladewas heat treated to achieve a Rockwell hardness of about RC 55. Theblade 100 was coupled to a blade driver 504. First, a 2.5 mm pilot holewas drilled into the femur 502. The guide member 424 was then insertedinto the pilot hole, and the blade 100 was advanced a distance of 20 mminto the femur 502. The blade reached the depth of 20 mm after about 7seconds, and with minimal tooth damage.

FIGS. 31-33 illustrate another configuration of the hub assembly 400similar to the embodiment of FIGS. 25A-29. Referring to FIGS. 31-33, theextension portions 434, 436, and 438 extend from the curved lowercoupling portion 404 of the hub member 402. More particularly, withreference to FIG. 33, the extension portions 434 and 438 extend fromrespective lateral or side portions 461, 463 of the coupling portion404, and the extension portions 436 and 440 can extend from a centralportion 465 of the coupling portion. In the illustrated embodiment, theextension portion 440 extends from the coupling portion 404 aboveextension portion 436 such that the extension portions 436 and 440 areradially spaced apart from each other relative to the axis 454.

The extension portions 436 and 440 can be configured to receive afastener configured as a set screw 460. As shown in FIG. 32, the lowerextension portion 436 can have a round shape, and can receive the head462 of the set screw 460 within a recess defined in the extensionportion 436. In certain embodiments, the lower extension portion 436 caninclude an anti-rotation feature configured as an anti-rotation tab 468.The anti-rotation tab 468 can be configured to prevent detachment of theblade 100 from the hub assembly due to vibration. With reference to FIG.33, the blade 100 can include a corresponding U-shaped notch or recess160 at or near the center of the proximal edge portion of the blade andextending distally from the proximal edge portion.

As shown in FIG. 33, the extension portions 434, 438 can each define arespective opening or slot 464, 466, and the blade 100 can includecorresponding extension portions or tabs 162, 164 spaced apart from eachother along the proximal edge of the blade. To secure the blade 100 tothe hub 402, the proximal end portion of the blade 100 can be insertedbetween the lower extension portion 436 and the upper extension portion440 such that the shank of the set screw 460 is received in the recess160 of the blade, and such that the tabs 162, 164 are received in thecorresponding openings 464, 466, as shown in FIGS. 31 and 32. The setscrew 460 can then be tightened to secure or clamp the blade between theextension portion 436 and the extension portion 440.

FIGS. 34-39A illustrate another embodiment of a hub assembly 600including a hub member 602 and a blade member 610 coupled to the hubmember 602. The hub member 602 can include an upper portion configuredas a hub portion 604 and a lower portion configured as a couplingportion 606. The hub portion 604 can be coupled to a chuck member 608similar to the chuck 410 of FIG. 21. As best illustrated in FIGS. 34-37,the chuck member 608 can be coupled to the hub portion 604 with athreaded fastener 612 that extends through an opening 614 (FIG. 36) inthe hub portion and engages corresponding threads in an opening 616(FIG. 37) defined in the chuck member 608. The coupling portion 606 canextend outwardly from the hub member 602, and can be configured toreceive the blade 610, which can be configured according to any of theblade embodiments described herein.

In certain configurations, the hub member 602 can be made by injectionmolding, or by an additive manufacturing process. For example, in someembodiments the hub member 602 can be three-dimensionally printed (“3Dprinted”) from any of a variety of polymeric or metallic materials. Theblade 610 can be coupled to the coupling portion 606 during the printingprocess, or after the printing of the hub member 602 is complete. Forexample, with reference to FIG. 36, in certain embodiments the couplingportion 606 can define a channel or slot 618 in an outwardly facing ordistal surface 636 of the coupling portion and extending along a lengthof the coupling portion 606. In the illustrated configuration, the slot618 is curved to match the curvature of the coupling portion and/or thecurvature of the blade 610. As shown in FIG. 39, the slot 618 can extendinwardly from the surface 636 through at least a portion of thethickness of the coupling portion 606.

Referring again to FIG. 36, the blade 610 can include a plurality of tabportions extending from a proximal edge portion 624 of the bladeopposite the blade teeth 626, similar to the blade 100 of FIG. 33. Inthe illustrated embodiment, the blade includes two tab portions 620,622, although the blade may include more or fewer tabs, depending uponthe particular application. The blade 610 can also include a recess orslot 628 defined on the proximal edge 624 (allowing the blade to beused, for example, with the hub member of FIG. 33). In certainembodiments, once the hub member 602 has been printed or otherwiseformed, the proximal edge 624 of the blade 610 can be inserted into theslot 618 in the manner indicated by arrow 630. In certainconfigurations, the blade can be press-fitted into the slot 618.

With reference to FIG. 38, the rear or proximal surface 640 of the hubmember 602 can include recesses or openings 632, 634 corresponding tothe tab portions 620, 622 of the blade 610. As best shown in FIG. 39,the openings 632, 634 can extend distally through the body of the hubmember such that the openings 632, 634 are in fluid communication withthe slot 618. Thus, when the blade 610 is inserted into the slot 618,the tabs 620 and 622 can extend into the respective openings 632 and634. The tab portions 620 and 622 can then be bent or folded over toengage the hub member. For example, in the illustrated configuration,the tab portions 620, 622 can engage respective interior surfaces,walls, or shoulders 638 of the openings to hold the blade 610 in place.In the illustrated configuration, the shoulders 638 are recessed withinthe openings 632, 634. However, in other embodiments, the hub assemblycan be configured such that the tab portions 620, 622 engage theproximal surface 640 of the hub member 602.

In some embodiments, once the tab portions 620 and 622 have been foldedto engage the shoulders 638, the hub member-blade assembly can then bepressed or rolled to further compress or form the material of thecoupling portion 606 around the blade 610 to hold the blade in place.The hub member 602 can also include more or fewer openings correspondingto the number of tab portions of the blade, as desired. In otherconfigurations, the hub member and blade can be configured such that theentire proximal edge portion 624 of the blade is folded over a shoulderor surface of the hub member.

In another embodiment, the blade 610 can be coupled or inserted into oron the coupling portion 606 of the hub member 602 during the printingprocess. For example, a portion of the coupling portion 606 of the hubmember 602 can be printed, and the blade 610 can be situated on thepartially printed coupling portion. The remainder of the hub member 602can then be printed around the blade 610 to capture the blade and createa one-piece, unitary construction. The tab portions 620 and 622 of theblade 610 can also be inserted into the openings 632 and 634 of the hubmember and folded to engage the hub member, as described above, beforethe printing of the hub member resumes. In certain embodiments, theblade 610 can also include one or more openings (e.g., similar to theopenings 152, 154 of FIG. 25B) on the proximal end portion 624 of theblade through which the material of the hub member 602 can flow orextend when printed or injection molded, as indicated schematically at642 in FIG. 39A. This can allow the hub member 602 to mechanicallyinterlock with the blade 610.

In certain embodiments, the chuck member 608 can be integrally formedwith the hub member 602, or can be separately attachable to the hubmember. As used herein, the terms “integrally formed” and “unitaryconstruction” refer to a construction that does not include any welds,fasteners, or other means for securing separately formed pieces ofmaterial to each other. For example, in some embodiments, the chuckmember 608 can be 3D printed with the hub member 602. In otherembodiments, the chuck member 608 can be made separately (e.g., from ametal, ceramic, or polymeric material), and attached to the hub member602. In certain embodiments, the hub member 602 may also include aninternal scaffolding structure around which the hub member is printed.In certain embodiments, the hub assembly 600 can be configured for usewith a guide member similar to the guide member 424 of FIG. 21.

In addition to the configurations and cutting structures describedabove, the blades described herein, such as the blade 100 and the blade610, can also provide a number of significant advantages related toblade material and thickness. For example, conventional stainless steelradial saw blades are typically heat-treated to harden the metal. Forexample, a conventional blade may be made from 17-4 PH stainless steelheat-treated to have a Rockwell hardness of 38 HRC to 44 HRC. The steelof such blades often exhibits elongation of 7% or less, and has highbrittleness properties. This can make the blades prone to breaking underbending loads, and requires that the blades have a thickness of greaterthan 0.02 inch, such as 0.03 inch or more, in order to compensate forthe high brittleness of the metal.

In contrast, the blade embodiments described herein can be made fromcold-drawn stainless steel sheet stock, such as type 316 cold-drawnstainless steel, without heat treatment. Blades made from suchcold-drawn steel exhibit high ductility properties, such as elongationof 15% or more, which is more than double the elongation exhibited bytraditional steel blades. Moreover, the blades can also have a Rockwellhardness of from 38 HRC to 45 HRC. Thus, the blades described herein canexhibit both high ductility and high hardness properties. The highductility allows the blades to be made significantly thinner thanexisting blades with a surprising ability to endure bending loadswithout fracture, as further described below. The high hardness providescutting efficiency and resistance to wear typically associated only withheat-treated blades of greater thickness.

As stated above, the combination of the high ductility and high hardnessparameters above allow the blades described herein to be madesurprisingly thin. For example, in some embodiments, the blades can havea thickness of 0.02 inch or less. In some embodiments, the blades canhave a thickness of from about 0.005 inch to about 0.018 inch. Inparticular embodiments, the blades can have a thickness of about 0.012inch. The reduced thickness of the blade allows the radius of the cutbone surface to precisely match the radius of the surface of the excisedbone segment, as described above, while the high ductility properties ofthe metal improve the blade's fracture resistance. Blades withthicknesses in this range can also offer advantages such as a reducedtendency to “walk” or “jump” across the bone surface when initiating acut, as compared to blades with higher thicknesses. In certainembodiments, the thickness of the blades can vary along the width of theblade, as in certain configurations described above, or can be constantalong the blade width, depending upon the particular characteristicsdesired.

FIG. 40A illustrates a cut made in a foam block 700 with a bladeaccording to the embodiments described herein having a thickness ofabout 0.012 inch (0.3 mm). As illustrated in FIG. 40A, the relativelysmall thickness of the blade results in a small gap between the mainfoam block 700 and a segment 702 cut from the block. The radii of thecut surfaces on the block 700 and on the segment 702 are closely matchedalong the full length of the cut. In the context of a bone, this reducesthe tendency of the segment to move with respect to the bone, therebyreducing the risk that the bone and the segment fail to unitepost-operatively.

FIG. 40B illustrates a similar cut made in a block 800 using a bladehaving a thickness of 0.0197 inch (0.5 mm), and FIG. 40C illustrates acut made in a block 900 using a blade having a thickness of 0.031 inch(0.8 mm). Relatively large gaps can be seen between the respectiveblocks 800, 900, and the segments 802, 902 cut from them, and the radiiof the cut surfaces do not match as closely as in the cut illustrated inFIG. 40A. Such gaps and mismatches in surface radii can significantlyincrease the risk of non-union outcomes in osteotomy procedures, and canbe addressed by the blade embodiments described herein havingthicknesses of 0.02 inch or less.

The blades described herein can also be cost-effectively manufactured.For example, the blades described herein can be made by acid etching orstamping metal sheet stock. This can significantly lower the cost andcomplexity of manufacturing compared to existing blades, which aretypically machined from bar stock. Because the blade and hub embodimentsdescribed herein can be cost-effectively manufactured, they can also becost-effectively replaced before the cutting efficiency of the bladesdegrades below a desired threshold. For example, FIG. 41 illustrates thedecline in cutting efficiency of a conventional blade as a function ofthe number of TPLO osteotomies performed. The replaceable blade designsdescribed herein allow the blades to be replaced quickly andcost-effectively before the cutting efficiency of the blades declinesbelow a surgeon's preferred threshold, which can avoid complicationssuch as binding, overheating of the bone, etc.

Additionally, although the blade and hub embodiments of the presentapplication are described with reference to veterinary medicalapplications, it should be understood that the blades, hubs, andmanufacturing techniques are also applicable to instruments in otherdisciplines, such as human medical instruments.

General Considerations

As used herein, the term “proximal” refers to a direction toward thepoint of origin or attachment, frequently toward the user in the contextof a surgical instrument.

As used herein, the term “distal” refers to a direction away from thepoint of origin or attachment, frequently away from the user in thecontext of a surgical instrument.

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein. Thedisclosed methods, apparatus, and systems should not be construed asbeing limiting in any way. Instead, the present disclosure is directedtoward all novel and nonobvious features and aspects of the variousdisclosed embodiments, alone and in various combinations andsub-combinations with one another. The methods, apparatus, and systemsare not limited to any specific aspect or feature or combinationthereof, nor do the disclosed embodiments require that any one or morespecific advantages be present or problems be solved.

Although the operations of some of the disclosed embodiments aredescribed in a particular, sequential order for convenient presentation,it should be understood that this manner of description encompassesrearrangement, unless a particular ordering is required by specificlanguage set forth below. For example, operations described sequentiallymay in some cases be rearranged or performed concurrently. Moreover, forthe sake of simplicity, the attached figures may not show the variousways in which the disclosed methods can be used in conjunction withother methods. Additionally, the description sometimes uses terms like“provide” or “achieve” to describe the disclosed methods. These termsare high-level abstractions of the actual operations that are performed.The actual operations that correspond to these terms may vary dependingon the particular implementation and are readily discernible by one ofordinary skill in the art.

As used in this application and in the claims, the singular forms “a,”“an,” and “the” include the plural forms unless the context clearlydictates otherwise. Additionally, the term “includes” means “comprises.”Further, the terms “coupled” and “associated” generally meanelectrically, electromagnetically, and/or physically (e.g., mechanicallyor chemically) coupled or linked and does not exclude the presence ofintermediate elements between the coupled or associated items absentspecific contrary language.

In some examples, values, procedures, or apparatus may be referred to as“lowest,” “best,” “minimum,” or the like. It will be appreciated thatsuch descriptions are intended to indicate that a selection among manyalternatives can be made, and such selections need not be better,smaller, or otherwise preferable to other selections.

In the following description, certain terms may be used such as “up,”“down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” andthe like. These terms are used, where applicable, to provide someclarity of description when dealing with relative relationships. But,these terms are not intended to imply absolute relationships, positions,and/or orientations. For example, with respect to an object, an “upper”surface can become a “lower” surface simply by turning the object over.Nevertheless, it is still the same object.

In view of the many possible embodiments to which the principles of thedisclosed technology may be applied, it should be recognized that theillustrated embodiments are only preferred examples and should not betaken as limiting the scope of the disclosure. Rather, the scope of thedisclosure is at least as broad as the following claims.

The invention claimed is:
 1. An assembly, comprising: a hub memberincluding a hub portion and a curved coupling portion, the curvedcoupling portion being radially offset from the hub portion with respectto a longitudinal axis of the hub portion about which the hub member isconfigured to rotate, the curved coupling portion including a slotdefined in a distal surface of the curved coupling portion, the hubmember further including at least one opening defined in a proximalsurface of the hub member, the at least one opening being in fluidcommunication with the slot of the curved coupling portion; and a sawblade received in the slot of the curved coupling portion, the saw bladecomprising: a main body including a first surface, a second surface onan opposite side of the main body from the first surface, a proximaledge portion, a distal edge portion comprising a plurality of cuttingteeth, and first and second side portions extending between the proximaland distal edge portions, the saw blade having a thickness of from 0.005inch to 0.018 inch; wherein the proximal edge portion comprises aU-shaped recess extending distally from the proximal edge portion, theproximal edge portion being coupled to the hub member such that the sawblade is held in a curved shape with the first surface defining an outerradius; and wherein the saw blade includes at least one tab portionextending through the at least one opening in the proximal surface ofthe hub member and folded over to engage the hub member.
 2. The assemblyof claim 1, wherein the at least one tab portion is folded over andengages a shoulder of the hub member, the shoulder being within the atleast one opening and offset from the proximal surface of the hubmember.
 3. The assembly of claim 1, wherein the saw blade ispress-fitted into the slot.
 4. The assembly of claim 1, wherein the sawblade includes one or more openings on a proximal end portion of the sawblade.
 5. The assembly of claim 4, wherein the hub member is injectionmolded or additively manufactured around the saw blade such thatmaterial of the hub member extends through the one or more openings inthe saw blade to mechanically interlock the saw blade to the hub member.6. The assembly of claim 1, wherein the saw blade has a thickness of0.012 inch.
 7. The assembly of claim 1, further comprising a chuckmember coupled to the hub portion, and configured to be coupled to ablade driver.
 8. The assembly of claim 1, wherein the second surfacecomprises a cutting structure configured such that a radius of an arcswept by the cutting structure when the saw blade is rotated issubstantially equal to the outer radius of the first surface.
 9. Theassembly of claim 1, wherein: the at least one tab portion is a firsttab portion; and the proximal edge portion further comprises a secondtab portion extending proximally from the proximal edge portion andspaced apart from the first tab portion along the proximal edge portion.10. The assembly of claim 9, wherein the first tab portion and thesecond tab portion are spaced apart from the U-shaped recess along theproximal edge portion.
 11. The assembly of claim 9, wherein the firsttab portion and the second tab portion are offset inwardly from thefirst side portion and the second side portion toward a longitudinalaxis of the saw blade such that the first tab portion and the second tabportion are closer to the longitudinal axis than outermost cutting teethof the plurality of cutting teeth.
 12. The assembly of claim 1, whereinwidth dimensions of respective base portions of the cutting teeth varyalong a width dimension of the saw blade.
 13. The assembly of claim 1,wherein the saw blade comprises cold-drawn stainless steel without heattreatment.
 14. The assembly of claim 1, wherein the saw blade comprisesa Rockwell hardness of 38 HRC to 45 HRC and an elongation of at least15%.
 15. An assembly, comprising: a hub member including a hub portionand a curved coupling portion, the curved coupling portion beingradially offset from the hub portion with respect to a longitudinal axisof the hub portion about which the hub member is configured to rotate,the curved coupling portion including a slot defined in a distal surfaceof the curved coupling portion, the hub member further including atleast one opening defined in a proximal surface of the hub member, theat least one opening being in fluid communication with the slot of thecurved coupling portion; and a saw blade received in the slot of thecurved coupling portion, the saw blade comprising: a main body includinga first surface, a second surface on an opposite side of the main bodyfrom the first surface, a proximal edge portion, a distal edge portioncomprising a plurality of cutting teeth, and first and second sideportions extending between the proximal and distal edge portions, thesaw blade having a thickness of from 0.005 inch to 0.018 inch; whereinthe proximal edge portion comprises a U-shaped recess extending distallyfrom the proximal edge portion, the proximal edge portion being coupledto the hub member such that the saw blade is held in a curved shape withthe first surface defining an outer radius; wherein the saw bladeincludes at least one opening on a proximal end portion of the sawblade, and the hub member is injection molded or additively manufacturedaround the saw blade such that material of the hub member extendsthrough the at least one opening in the saw blade to mechanicallyinterlock the saw blade to the hub member.
 16. The assembly of claim 15,wherein the saw blade includes at least one tab portion extendingthrough the opening in the proximal surface of the hub member and foldedover to engage the hub member.
 17. The assembly of claim 16, wherein theat least one tab portion is folded over and engages a shoulder of thehub member, the shoulder being within the at least one opening andoffset from the proximal surface of the hub member.
 18. The assembly ofclaim 17, wherein: the at least one tab portion is a first tab portion;and the proximal edge portion further comprises a second tab portionextending proximally from the proximal edge portion and spaced apartfrom the first tab portion along the proximal edge portion.
 19. Theassembly of claim 15, wherein the saw blade comprises cold-drawnstainless steel without heat treatment.
 20. The assembly of claim 15,wherein the saw blade comprises a Rockwell hardness of 38 HRC to 45 HRCand an elongation of at least 15%.
 21. An assembly, comprising: a hubmember including a hub portion and a curved coupling portion, the curvedcoupling portion being radially offset from the hub portion with respectto a longitudinal axis of the hub portion about which the hub member isconfigured to rotate, the curved coupling portion including a slotdefined in a distal surface of the curved coupling portion, the hubmember further including openings defined in a proximal surface of thehub member, the openings being in fluid communication with the slot ofthe curved coupling portion; and a saw blade received in the slot of thecurved coupling portion, the saw blade comprising: a main body includinga first surface, a second surface on an opposite side of the main bodyfrom the first surface, a proximal edge portion, a distal edge portioncomprising a plurality of cutting teeth, and first and second sideportions extending between the proximal and distal edge portions, thesaw blade having a thickness of from 0.005 inch to 0.018 inch; whereinthe proximal edge portion comprises a U-shaped recess extending distallyfrom the proximal edge portion, the proximal edge portion being coupledto the hub member such that the saw blade is held in a curved shape withthe first surface defining an outer radius; and wherein the saw bladeincludes a first tab portion and a second tab portion extending throughthe openings in the proximal surface of the hub member and folded overto engage the hub member to secure the saw blade to the hub member.